Express your answer as a mixed number simplified to lowest terms. $12\dfrac{3}{9}-5\dfrac{1}{9} = {?}$
Solution: Separate the whole numbers from the fractional parts: $= {12} + {\dfrac{3}{9}} - {5} - {\dfrac{1}{9}}$ Bring the whole numbers together and the fractions together: $= {12} - {5} + {\dfrac{3}{9}} - {\dfrac{1}{9}}$ Subtract the whole numbers: $=7 + {\dfrac{3}{9}} - {\dfrac{1}{9}}$ Subtract the fractions: $= 7+\dfrac{2}{9}$ Combine the whole and fractional parts into a mixed number: $= 7\dfrac{2}{9}$